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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // api: https://api.apiopen.top/getJoke

        const p = new Promise((resolve, reject) => {
            // 1. 创建对象
            const xhr = new XMLHttpRequest();
            // 2. 初始化
            xhr.open('GET', 'https://api.apiopen.top/getJoke');
            // 3 .发送
            xhr.send();
            // 4. 处理响应
            xhr.onreadystatechange = function() {
                if (xhr.readyState === 4) {
                    if (xhr.status >= 200 && xhr.status <= 299) {
                        resolve(xhr.response)
                    } else {
                        reject(xhr.response)
                    }
                }
            } 
        })
        
        p.then(res => {
            console.log(res)
        }, err => {
            console.error(err)
        })

    </script>
</body>
</html>